Internal combustion engine having two-stage exhaust-driven supercharger and charge air cooling between low pressure and high pressure compressors

ABSTRACT

The invention relates to an internal combustion engine with a 2-stage charge loading. A connection conduit ( 13 ) with a supercharger intercooler ( 14 ) is provided between the compressor of the low pressure stage and that of the high pressure stage. The supercharger intercooler ( 14 ) is inventively characterized in that it is configured via a cooling unit ( 15 ) in the charge air guiding connection conduit ( 13 ) between the compressor ( 8 ) of the ATL-low pressure stage ( 7 ) and the compressor ( 5 ) of the ATL-high pressure stage ( 4 ) having a cooling medium flowing therethrough as well as by a specially configured section ( 16 ) of the connection conduit ( 13 ), whereby the connection conduit ( 13 ) in this section ( 16 ) forms with its wall ( 17 ) the outer wall of the supercharger intercooler ( 14 ) and, via corresponding shape accommodating configuration thereof, delimits an air through-put volume sufficient to effect, via a cooling medium flowing through the cooling unit ( 15 ), an acceptable cooling of the charge air flowing through the cooling unit ( 15 ) that itself is built into the connection conduit.

The invention relates to an internal combustion engine with a 2-stage exhaust gas turbo loader and with a supercharger intercooler in the connection conduit between the compressor of the low pressure stage and the compressor of the high pressure stage.

An internal combustion engine with such features is known, for example, from DE 19961610 A1. With regard to this disclosure, a supercharger intercooler is, in fact, provided between the compressor of the low pressure stage and that of the high pressure stage; however, it remains open how this supercharger intercooler is configured.

It is therefore the object of this invention to provide a supercharger intercooler that takes into account the space-constrained relationships in the internal combustion engine between the low pressure- and high pressure-compressors.

This object is solved for an internal combustion machine of the state of the art having, in accordance with the invention, by a supercharger intercooler having the characteristics as set forth in claim 1.

Advantageous embodiments of the inventive solution are characterized in the dependent claims.

The inventive supercharger intercooler is characterized via extremely small but nonetheless effective configurations. In view of the fact that the cooling unit can be built in in the manner of a cartridge in a specially configured section of the connection conduit between the ATL-low pressure compressor and the ATL-high pressure compressor and this section of the connection conduit forms the outer wall of the supercharger intercooler, a simple manufacturing of this component is, on the one hand, possible and, on the other hand, a simple mounting of this same component between the pair of ATL-stages is possible. A sufficiently large cooling effect is thus achieved, because the cooling pipes are provided exteriorly with a plurality of cooling ribs that operate to effect a corresponding heat exchange.

The inventive supercharger intercooler is described in more detail hereinafter with reference to an embodiment illustrated in the drawings. The drawings show:

FIG. 1 diagrammatic view of an internal combustion machine with a 2-stage charger and supercharger or charge air cooling between the low pressure- and high pressure-stages,

FIG. 2 a sectional view of an embodiment for an inventive cooling unit,

FIG. 3 a cover belonging to the embodiment shown in FIG. 2,

FIG. 4 an embodiment of a connection conduit section, between both compressors of the ATL-stages, that is a portion of the inventive supercharger intercooler,

FIG. 5 an embodiment of the inventive supercharger intercooler in connection with the deployment of the cooling unit according to FIG. 2, the cover according to FIG. 3, and the connection conduit section according to FIG. 4,

FIG. 6 a cross-sectional view through the illustration of FIG. 5 along the thereat-delineated section line VI-VI.

In FIG. 1, a supercharged internal combustion engine is shown whose exhaust gas collector conduit that is connected with the outlet channels of the cylinder is designated with 2 and whose charge air collector conduit that is connected with the inlet channels of the cylinder is designated with 3. The internal combustion engine 1 has a 2-stage exhaust gas turbo charger arranged relative thereto whose high pressure stage 4 comprises a turbine 6 that drives a compressor 5 and whose low pressure stage 7 comprises a turbine 9 that drives a compressor 8. The turbine 6 of the high pressure stage 4 is connected via an exhaust gas channel 10 with the exhaust gas collector conduit 2 and is connected via a connection channel 11 with the turbine 9 of the low pressure stage 7. The compressor 5 of the high pressure stage 4 is connected via a charge air conduit 12 with the charge air collector conduit 3 and is connected via a connection channel 13 with the compressor 8 of the low pressure stage 7. A supercharger intercooler 14 is provided in the connection conduit 13. This supercharger intercooler 14 is configured in accordance with the invention and as hereinafter further described.

In accordance with the invention, the supercharger intercooler 14 is configured—see FIG. 2—via a cooling unit 15 having a cooling medium flowing therethrough in the charge air guiding connection conduit 13 and a specially configured section 16 of the connection conduit 13—see FIG. 3, 4—whereby the connection conduit 13 in this section 16 forms, via its wall 17, the outer wall of the supercharger intercooler 14 and, via corresponding shape-accommodating configuration thereof, delimits an air through-put volume sufficient to effect, via a cooling medium flowing through the cooling unit 15, an acceptable cooling of the charge air flowing through the cooling unit 15 that itself is built into the connection conduit.

As can be well seen in FIG. 2, the cooling unit 15 is configured in the manner of a pre-assembled cartridge. This cooling unit 15 is comprised of a base plate 18 and several, such as, for example, three, cooling pipes 19, 20, 21 provided exteriorly with a plurality of cooling ribs—see FIG. 6. In this connection, each cooling pipe 19, 20, 21 comprises on one end thereof a cylindrical band 22 by which the cooling pipe is installed on the base plate 18 perpendicularly thereto in a blind hole bore 23 of the base plate 18, the installation being effected, for example, via pressing in, welding in, or soldering in of the cooling pipe. Each cooling pipe 19, 20, 21 supports, at its other end on a cylindrical band 24, a sealing tube 25. Within the cooling unit 15, each cooling pipe 19, 20, 21 communicates via its inner bore 26 with a distribution channel 27 configured in the base plate 18.

The connection conduit 13 is comprised, in each section 16 forming the supercharger intercooler 14, of a substantially straight cooling pipe section 16 and two elbows 30, 31 each on a respective end region of the straight cooling pipe section and laterally deviating therefrom before the axial ends 28, 29 thereof. In this manner, the cooling unit 15, which is configured in the manner of a cartridge, is disposable during its final assembly through an open end 28 of the straight section 16 of the connection conduit 13 into the interior volume of the connection conduit, whereby the cooling unit is, via the sealing tubes 25 on the cooling pipes 19, 20, 21, inserted in a sealing manner into retaining bores 32 formed in the axial ends 29 of the section 16 that are oppositely disposed to the cooling pipes and, thereafter, is, via several bolts 33, secured with its base plate 18 on an axial end 28 in a leak-free manner. Thereafter, the straight section 16 of the connection conduit 13 is closed on its ends 29 neighboring the sealing tubes 25 via a securable cover 34 disposed thereat. This cover 34 comprises, internally, a distribution channel 36 that can be supplied from the exterior—see arrow 35—with cooling medium, the distribution channel being communicated with a portion of the cooling pipes—namely, the cooling pipes 20, 21. Furthermore, the cover 34 comprises, internally, a return flow channel 38 connected with an external cooling medium return conduit—designated via arrow 37, the other one remaining cooling pipe or the other remaining cooling pipes—here, namely, the one remaining cooling pipe 19—communicating with the return flow channel.

In the illustrated example, the inventive cooling unit 15 comprises three cooling pipes 19, 20, 21 arranged in a plane in parallel neighboring relationship to one another with limited spacing from one another and having the same length and configuration—see FIG. 6—whereby cooling medium is flowed through two of these (20, 21) in parallel in one direction—see arrow 39 in FIG. 5—and cooling medium is flowed through the third cooling pipe 19 in the other direction—see arrow 40—and quasi forms a cooling insert internal cooling medium-return conduit.

With its wall 17, the connection conduit 13 encloses within its straight channel section 16 the built in cooling unit 15 at a predetermined, not large spacing therefrom that is smaller than the outer diameter of the cooling pipes 19, 20, 21.

Via this inventive supercharger intercooler 14, an adequate cooling effect is achieved, despite the very small size of the supercharger intercooler, by virtue of the intensive flow through the cooling pipes 19, 20, 21 of the cooling medium and the inner contact of the charge air, which flows through the cooling unit 15 in the connection channel-section 16, with the cooling ribs of the cooling pipes 19, 20, 21. 

1-5. (canceled)
 6. An internal combustion engine with a 2-stage exhaust gas turbo charger (ATL) having a low pressure stage and a high pressure stage, the combustion engine comprising: a charge air guiding connection conduit having a wall; and a supercharger intercooler in the connection conduit at a location therein between a compressor of the low pressure stage and a compressor of the high pressure stage, the supercharger intercooler having a cooling unit in the charge air guiding connection conduit between the compressor of the low pressure stage and the compressor of the high pressure stage having a cooling medium flowing therethrough, the connection conduit having a section and the wall of the charge air guiding connection conduit forming the outer wall of the supercharger intercooler and, via corresponding shape-accommodating configuration thereof, delimiting an air through-put volume sufficient to effect, via a cooling medium flowing through the cooling unit, an acceptable cooling of the charge air flowing through the cooling unit that itself is built into the connection conduit.
 7. An internal combustion engine according to claim 6, wherein the cooling unit is configured in the manner of a pre-assembled cartridge and is comprised of a base plate as well as several cooling pipes provided exteriorly with a plurality of cooling ribs, whereby each cooling pipe: has on one end thereof a cylindrical band by which the cooling pipe is installed on the base plate 18 perpendicularly thereto in a blind hole bore of the base plate 18, the installation being effected, for example, via pressing in, welding in, or soldering in of the cooling pipe, and on its other end supports, on a cylindrical band, a sealing tube, and whereby each cooling pipe has an inner bore communicating with a distribution channel configured in the base plate.
 8. An internal combustion engine according to claim 7, wherein the connection conduit comprises a substantially straight cooling pipe section and two elbows on a respective end region of the straight cooling pipe section and laterally deviating therefrom before axial ends of the straight cooling pipe section, whereby the cooling unit, which is configured in the manner of a cartridge, is disposable during its final assembly through an open axial end of the straight cooling pipe section into the interior volume of the substantially straight cooling pipe section and is thereby inserted in a sealing manner, via sealing tubes on the cooling pipes, into retaining bores formed on the connection conduit in the axial ends of the straight section that are oppositely disposed to the cooling pipes and is, with its base plate, securable in a flanged leak-free manner on an axial end, and whereby the straight section of the connection conduit is closed on its ends neighboring the sealing tubes via a securable cover disposed thereat that communicates internally with a portion of the cooling pipes via a distribution channel that can be supplied from the exterior with cooling medium, and furthermore comprises internally a return flow channel, communicated with an external cooling medium return conduit, that is communicated with the other remaining cooling pipe(s).
 9. An internal combustion engine according to claim 8, wherein the cooling unit, which is configured in the manner of a cartridge, comprises three cooling pipes arranged in parallel neighboring relationship to one another in a plane and having the same length and configuration, whereby cooling medium is flowed through two of these in parallel in one direction and cooling medium is flowed through the third cooling pipe in the other direction and quasi forms a cooling insert internal cooling medium-return conduit.
 10. An internal combustion engine according to claim 9, wherein the connection conduit encloses, with the wall, the built in cooling unit within the section, with the wall being at a spacing that is smaller than the diameter of the cooling pipes. 